There is a conventional outdoor unit for an air-conditioning apparatus, which includes an air path chamber including a heat exchanger disposed at least on the rear side within the unit, a propeller fan disposed on the front side of the heat exchanger and having a plurality of blades, and a bell mouth disposed on the front side of the propeller fan, a machine chamber in which a compressor is disposed, and a partition plate that separates the air path chamber and the machine chamber. A recessed area protruding toward the machine chamber is provided in an area of the partition plate corresponding to the dimension, in the direction in which the propeller fan rotates, of the outer peripheries of the blades in the air path chamber (see, for example, Patent Literature 1).